In a high power, ultra wideband (“UWB”) feed forward linear power amplifier (“FFLPA”), it may not be economical to obtain components which cover the full bandwidth required of the FFLPA. This is especially true for an error correction path, which must operate over a wider bandwidth than the FFLPA, in order to remove distortion products that may fall outside an operating bandwidth of the FFLPA. In such configurations, therefore, there tends to be an inability to obtain a sufficient error correction bandwidth in a very wide bandwidth FFLPA, for example, where the linear power amplifier (“LPA”) bandwidth equals the maximum practical error amplifier bandwidth.
Known devices include a “dual loop” FFLPA, in which two error correction loops are tuned and aligned to operate across the same frequency range. This approach may provide enhanced error correction. However, it can limit the operating bandwidth of the FFLPA to about half the bandwidth of each error correction path. If this approach is utilized, an octave bandwidth FFLPA (for example) would require an error correction path having about a two octave bandwidth.
Multiple octave power amplifiers are known, but tend to be inefficient and hence generally utilized in laboratory and cost-insensitive military applications.